Process for manufacturing microkeratome blade

ABSTRACT

An improved process for the manufacture of uniform and accurately sized thin metal blades, particularly for Microkeratome blades used in the Lasik eye correction procedure. The steps comprise qualifying raw blades stock with an accurately positioned dowel hole. Once the raw blade stock is qualified, individual blades are stacked one on top of each other via the accurately positioned dowel hole. Multiple raw blades, stacked one on top of another, are clamped. The wire EDM process is then used to cut precise geometries through individual blades, which are accurately stacked one on top of each other. This process is unique in that multiple blades and individual sharp edges are stacked such that all sharp edges have the same leading edge location.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] U.S. Provisional Patent Application No. 60/180,119

FIELD OF THE INVENTION

[0002] This invention relates to a method for the manufacturing of uniform sharp blades of various configurations for use in procedures that may relate to medical treatment and surgery.

BACKGROUND OF THE INVENTION

[0003] Sharp surgical blades and to a lesser degree standard surgical blades are increasingly important in the medical device field. In particular, the Mircokeratome blade is used in the Lasik eye correction procedure to facilitate the formation of a corneal flap. For instance, in order to correct myopia, a laser provides pulses of radiation energy to resurface the cornea. This resurfacing results in a correction of the optical interface such that images are focused on the retina. The sharp surgical blade used to generate the corneal flap is known as a Microkeratome. The corneal flap depth is precisely controlled using a Keratome and Microkeratome blade. As such, the exact dimension of the Microketatome blade and its positioning are of a precise magnitude.

[0004] Two key requirements for the manufacturing of the Microkeratome blades include an extremely clean, non-contaminated surface and an extremely accurate leading edge. As such, detecting the leading edge of a blade and developing a manufacturing process to process multiple units in a high yield and repeatable fashion is extremely important. The proposed invention and process addresses the difficulty associated with manufacturing large volume surgical blades of precise location from a sharp leading edge. The sharp leading edge is produced via grinding and polishing under standard manufacturing conditions. The accurate cutting of the raw strip involves the wire EDM manufacturing process and various fixtures to facilitate accurate manufacturing.

[0005] It is a principle objective of the present invention to provide a series of manufacturing steps that provides for a uniformly positioned dowel hole on a raw strip blade. The uniform dowel hole facilitates stacking of multiple blades, which provides for an efficient means of manufacturing Microkeratome blades. It will be understood that although the description of the invention will proceed with reference to the manufacturing of Mircokeratome blades or other similar types of surgical blades, the technologies disclosed in the application should be based on other technologies for manufacturing precise thin blade material.

[0006] It is a further objective of the invention to provide a process, which provides for a cost effective method of manufacturing.

SUMMARY OF THE INVENTION

[0007] The method of fabricating Microkeratome blades first involves qualifying the bladestock, since raw bladestock will have various widths. The qualification process involves precisely determining the blade edge and machining a dowel hole a precise distance from that edge, which is used as a location point for stacking individual blades.

[0008] The location of a dowel hole provides for an extremely accurate position and reference point with which to stack multiple raw blades. Each raw blade has a relative position to the next raw blade edge, which is identical. i.e.: all sharp leading edge points are of the same reference datum. The stacked fixture, which accommodates the dowel blade provides for multiple stacking operations. A further advantage of the invention is the utilization of multiple stacking points to facilitate long unattended EDM operations. A further benefit of the invention is the uniform method in which the entire fixture may be cleaned and dried and prepared for inspection.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The method of the invention will now be described with reference to the accompanying drawings, in which:

[0010]FIG. 1 Is an engineering drawing depicting a standard Microkeratome raw strip with locating holes.

[0011]FIG. 2 Is an engineering drawing depicting raw blades stocks loaded onto multiple cavity dowel fixtures.

[0012]FIG. 3 Depicts the multi-cavity dowel fixture with dowel blade clamps attached and secured.

[0013]FIG. 4 Represents an engineering drawing of a completed blade strip with appropriate dowel holes.

[0014]FIG. 5 Represents a stacked fixture with appropriate dowel pin and stacked dowel pin location.

[0015]FIG. 6 Represents stacked fixture with appropriate clamps.

[0016]FIG. 7 Represents stacked fixture following the EDM process and individual Mircokeratome blades.

[0017]FIG. 8 Represents an individual Microkeratome blade with reference to critical dimensions from leading sharp edge.

[0018]FIG. 9 Represents a schematic outline of the manufacturing process disclosed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] With reference to FIG. 1, item 101 depicts the raw keratome blade with locating holes 100 and leading sharp edge 102.

[0020] Referring to FIG. 2, Raw blade 101 is placed on dowel fixture 202 and located off of dowel stop 201. Dowel stop 201 provides a general location point with which to reference leading edge 102, depicted in FIG. 1.

[0021] Referring to FIG. 3, once the doweling fixture is loaded with raw keratome blades, the blade and fixture are clamped using clamp 300. Clamp 300 is secured via standard socket set screws. The entire dowel fixture is then placed on standard wire EDM equipment. The EDM manufacturing cycle and program uses electrical continuity to determine the exact position of the leading sharp edge 102 depicted in FIG. 1. By moving in very small increments, a test for conductivity is performed. If no conductivity is detected, an increment of 0.000050″ is initiated. This process is repeated until conductivity is detected. Multiple conductivity tests are taken with an average to determine the exact blade edge 102. Once the exact blade position of blade 102 is determined, the wire EDM process provides for an accurate dowel location 400. This process is repeated in multiple areas of the keratome strip.

[0022] In FIG. 4, three individual dowel locations are described. Once the doweling process is completed, individual dowel blades are removed from dowel fixture 202.

[0023] In FIG. 5, Blades are then placed on stacked fixture 500 over dowel pin 502. Multiple blades are stacked on 500 such that each edge and dowel pin have been pre-qualified to provide for a uniform parallel sharp edge surface.

[0024]FIG. 6 depicts that once an appropriate stack height is achieved, the entire stack is secured using two-segment clamp 600. The two-section clamp 600 provides for the securing of the scrap and the final product. Exact edge location again utilizes general electrical continuity. In this case, continuity is performed in a similar manner except that all individual blades provide for a single contact point via the precise dowel location described in FIG. 4. Precise geometries and locating points can now be machined using standard wire EDM technology.

[0025] Referring to FIG. 7, the exact location of locating hole 100 is performed by referencing the exact datum provided for in qualifying dowel fixture. The general manufacturing process is repeated for multiple locations to provide for a system of systematically manufacturing ultra-precise thin surgical blades with reference to sharp leading edge.

[0026]FIG. 8 depicts two dimensions, Dimension X and Y. Dimension X is controlled by knowing the precise location provided for in the doweling step.

[0027]FIG. 9 shows a schematic flow chart of the method of manufacturing disclosed herein for the manufacture of uniform blades that may be used in surgery. FIG. 9 shows that the first step being the qualifying of blade stock, and then the attachment of the blade to the dowel fixture. The next step in the manufacture is the securing of the dowel blade onto the stacked fixture. After the stacked fixture and machining is done the result are either Microkeratome blades or scrap material. 

What is claimed:
 1. A method for the manufacturing of accurately sized surgical blades having a desired geometry and having the same leading edge distance that is comprised of the steps of qualifying and doweling individual leading edges, and stacking individually qualified and doweled leading edges, and manufacturing multiple stacked units from stacked components, whereby: a method for the qualifying of the individual blades whereby electrical continuity is used to determine the exact position of the sharp ultra-thin leading blade edge, and whereby, the blades are stacked against onto a dowel or similar stop, and the dowel is used to qualify the exact position of the sharp ultra-thin leading blade edge used, and a cleaning solution is used to remove brass residue from the surgical blades including the use of an oxidation inhibition bath and drying sequence including burst of dry air and centrifuge. 